Summary:
Hostile mobs can spawn inside azaleas and flowering azaleas.

Steps to Reproduce:

1. Create a new world
2. Fly high up in the air
3. Type the following command:

   /fill ~10 ~ ~10 ~-10 ~ ~-10 moss_block
   

4. While standing on the moss blocks, type the following command:

   /fill ~10 ~ ~10 ~-10 ~ ~-10 azalea
   

5. Set the time to midnight

Observed Results:
Hostile mobs spawn inside azaleas and flowering azaleas.

Expected Results:
Hostile mobs should not spawn inside or on top of azaleas and flowering azaleas.

Screenshot: